A multi-hop ad-hoc wireless mesh network made up of a plurality of nodes and a plurality of links between the nodes. Routing in such networks is carried out by data being forwarding data to other nodes so that data passes from a source node to a destination node as a series of hops. A multi-hop ad-hoc wireless mesh network is considered to be fully reachable if any given node of the network can be reached from any other given node with an arbitrary number of waypoints and hops.
Examples of multi-hop ad-hoc wireless mesh networks are a disaster-relief or defense device drops. For example, swarm of sensor nodes may be dropped over a wide area to gather information. The sensor nodes can be anything from gas/radiation detectors to sensitive seismographs. Information can then be collated from all nodes. Another example is dropping a swarm of multi-hop communications relays over a wide area to re-establish communications where the primary infrastructure has been destroyed. Further examples are a pop-up mote array providing connectivity at an event such as a festival and a communications or sensor array in a shopping mall.
A node is considered to be a critical node in a fully reachable network if the removal or failure of that node results in the network no longer being fully reachable.